Calling in what's owed to me

A so-called friend stole £200 from me several years ago and she borrowed £50 off me prior (she still owes me £40 of that debt). She never returned the £200, and several people covered up for her thieving.

Is it going too far to use a bit of magic to get her to pay me the £240 she owes me, and to cause someone to do it to her (so that she’ll know how it feels for a so-called friend to do that to you)? Or should I stick to just getting the money she owes me? As you can tell I’m a bit torn.

Ask for the money back and a reasonable interest rate in addition.